Conventionally, for example, in a network configuration illustrated in FIG. 1, nodes D, A, B, C, and E use a routing protocol (see RFC2328 and RFC3630) such as Open Shortest Path First-Traffic Engineering (OSPF-TE) to advertise link information containing associated area information “areas 1, 2, and 3,” and construct topology information (see FIG. 2) of an entire network.
When an instruction to set a path is received, the start-point node D of the path computes a route from a start point to an end point, and transfers a signaling message (Path message) containing route information “A, B, C, E” using a signaling protocol (see RFC2205, RFC3209, RFC3471, and RFC3473) such as Resource Reservation Protocol-Traffic Engineering (RSVP-TE). The signaling message further contains end-to-end end-point node information and connection end-point node information.
An end-to-end path from the start-point node D to the end-point node E is divided into connections for each of external network to network interface (ENNI) domains and internal network to network interface (INNI) domains. The start-point node A of an INNI connection sequentially searches, based on route information “B, C, E” in the signaling message and the topology information held, through the nodes on the route to check if any one of which is an area boundary, finds the end-point node C of the INNI connection, stores “C” as the connection end-point node information in the signaling message, and transfers the signaling message to the next node B.
Upon receiving the signaling message, the next node B judges if the connection end-point node information “C” is an own node (a local node). When the local node is the end-point node C, the node B performs a connection end-point processing, and further transfers the signaling message to the node E next thereto.
In this conventional technology, there is a need for the start-point node A of the INNI connection to sequentially search, based on the route information “A, B, C, E” in the signaling message and the topology information held, for the end-point node C of the INNI connection.
The start-point node A of the INNI connection sequentially searches, based on the route information “B, C, E” in the signaling message, the topology information illustrated in FIG. 2 to check with which area each of the A-B link, the B-C link, and the C-E link is associated, judges the node C to be the area boundary, and sets the node C as the end-point node of the connection.
However, with this approach, as a number of hops in the INNI connection increases (2 hops in the example of FIG. 1), the processing load in judging the end point of the INNI connection inevitably increases in proportion thereto.
The following are related arts to the invention.
[Patent document 1] Japanese Patent Laid-Open Publication No. JP 2006-121249
[Non-patent document 1] RFC2328, RFC3630; draft-ietf-ccamp-gmpls-ason-routing-ospf-02.txt, OIF2005.313.08, etc.
[Non-patent document 2] RFC2205, RFC3209, RFC3471, RFC3473;
OIF2005.381.09-Draft OIF E-NNI Signaling Specification (OIF E-NNI 2.0), etc.